The present invention relates to electromagnetic compatibility of switch-mode power converters of a connected light node induction light ballast module.
Federal Communications Commission (FCC) rules and regulations contained in Title 47 mandates standards that require any electronic system with a switching device operating in excess of 9 kHz, for intentional and unintentional RF transmitters, switching power systems, to comply with FCC following requirements:
(A) Conducted Emission: FCC Part 15 (150 kHz-30 MHz, Average and Quasi Peak Limits). Industrial applications are classified as Class A requirements.
(B) Conducted Emission: FCC Part 18 (450 kHz-30 MHz, for Wireless Light Modules). Industrial applications are classified as Class A requirements.
(C) Radiated Emission FCC Part 15 (30 MHz-1000 MHz, Quasi Peak Limits). Industrial applications are classified as Class A requirements.
The invention is directed to resolving and mitigating EMI non-conformance with respect to Conducted Emission and Radiated Emission requirements per FCC. Class A part 15 and part 18 specifications for a connected light node induction light ballast module providing power to an induction lamp.
Providing a capacitive plate shunt element is a concept that has been considered as a mitigation technique for conducted emission failure by Electromagnetic Compatibility (EMC) experts. However, the inclusion of a capacitive shunt plate increases radiated emission profile and results in radio frequency (RF) noise energy (spectral shift of RF energy content to higher frequencies). More critically, addition of a capacitive plate shunt element may create structural resonances, which will contribute to radiated emission non-compliance. As a result of this, the capacitive plate shunt concept has been avoided.
Creation of any unintended structural radiating antennas, i.e., as a result of a capacitive shield or from a metallic enclosure that alters or modifies the magnitude and direction of common mode RF currents are issues with regard to EMI non-conformance. Thus, such factors must be compensated for to obtain Conducted Emission and Radiated Emission field Compliance.
A mitigation device must be adaptable for application to a large variety of high frequency switching circuits and correlate well with full FCC measurements and standards. The mitigation device and components must employ an arrangement to limit the level of RF currents on external cables of an induction light ballast module to ensure full EMI compliance as per FCC requirements delineated earlier.